An analog to digital conversion circuit and method is presented. The analog to digital circuit (100) comprises a first capacitor (103), arranged for being switchably (102) connected on one side to an input voltage (101), at least one successive approximation circuit (104), a comparator (108) arranged for outputting a sign indicative of the difference between the voltage on the first capacitor (103) and a comparison voltage (109), and a control block (110), arranged for converting said comparator's output into steering signals and in a digital output signal. The successive approximation circuit comprises a second capacitive structure (106), switchably connected to a pre-charge circuit (107) arranged for pre-charging the second capacitive structure (106), whereby the second capacitive structure (106) is connected in parallel with the first capacitor (103) via a charge copying circuit (105). The steering signals comprise of a signal for steering (112) said charge copying circuit (105) and for steering (113) the pre-charge circuit (107).